2012-00589 - new structure - Laserfiche WebLink

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2.03 Geosynthetic Reinforcement A. Geosynthetic reinforcement shall consist of high-tenacity PET geogrids,HDPE geogrids, or geotextiles manufactured for soil reinforcement applications. The type, strength and placement of the geosynthetic reinforcement shall be determined by procedures outlined in this specification and the NCMA Design Manual for Segmental Retaining Walls(3rd Edition 2009) and materials shall be specified by Wall Design Engineer in their final wall plans and specifications. The manufacturers/suppliers of the geosynthetic reinforcement shall have demonstrated construction of similar size and types of segmental retaining walls on previous projects. The geosynthetic type must be approved one week prior to bid opening. Geosynthetic types currently approved for this project are: VERSA-Grid Geogrids B. The type, strength and placement of the reinforcing geosynthetic shall be as determined by the Wall Design Engineer,as shown on the final, P.E.-stamped retaining wall plans. 2.04 Leveling Pad A. Material for leveling pad shall consist of compacted sand, gravel, or combination thereof (USCS soil types GP,GW, SP, & SW)and shall be a minimum of 6 inches in depth. Lean concrete with a strength of 200-300 psi and 3 inches thick maximum may also be used as a leveling pad material. The leveling pad should extend laterally at least a distance of 6 inches from the toe and heel of the lowermost SRW unit. 2.05 Drainage Aggregate A. Drainage aggregate shall be angular, clean stone or granular fill meeting the following gradation as determined in accordance with ASTM D422: Sieve Size Percent Passing 1 inch 100 3/4 inch 75-100 No. 4 0-60 No. 40 0-50 No. 200 0-5 2.06 Drainage Pipe A. The drainage collection pipe shall be a perforated or slotted PVC,or corrugated HDPE pipe. The drainage pipe may be wrapped with a geotextile to function as a filter. 4